channeldb: check fetchOpenChannel() error

docs/release-notes/release-notes-0.14.1.md

@@ -3,7 +3,9 @@
 ## Bug Fixes
 
 * [Fixed an inaccurate log message during a compaction failure](https://github.com/lightningnetwork/lnd/issues/5937)
+* [A bug has been fixed in channeldb that uses the return value without checking error](https://github.com/lightningnetwork/lnd/pull/6012)
 
 # Contributors (Alphabetical Order)
 
-* Jamie Turley
+* Jamie Turley
+* nayuta-ueno